1. Field of the Invention
The present invention relates to an image forming apparatus and control method thereof and, more particularly, to an image forming apparatus and control method thereof for forming a color image by superimposing images of a plurality of color components using a plurality of image carriers.
2. Description of the Related Art
There has conventionally been known an image forming apparatus which forms a color image by sequentially superimposing a plurality of images of different colors. This color image forming apparatus suffers so-called color misregistration if the image forming position of any color deviates from those of the remaining colors.
As a method for reducing the color misregistration, the image forming position is corrected by performing image processing for image data to convert a readout address in an image memory or the like so as to cancel a positional error generated in exposure scanning (see, for example, Japanese Patent Laid-Open No. 2006-159452).
However, the conventional correction method based on image data readout address conversion causes moiré or jaggies at the edge of a character or line art upon correction. To suppress the generation of moiré or jaggies, the image forming apparatus requires an edge detection unit for detecting an edge, and an exceptional processing unit for applying exceptional processing to the detected edge. This arrangement is disadvantageous in both apparatus size and processing time.